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XGetFeedbackControl(3)





NAME

       XGetFeedbackControl,  XChangeFeedbackControl  -  query and change input
       device feedbacks


SYNTAX

       XFeedbackState *XGetFeedbackControl(Display *display, XDevice  *device,
              int *num_feedbacks);

       int  XChangeFeedbackControl(Display  *display,  XDevice  *device,  Mask
              mask, XFeedbackControl *control);


ARGUMENTS

       display        Specifies the connection to the X server.

       device         Specifies the device whose feedbacks are to  be  queried
                      or modified.

       num_feedbacks  Specifies  an address into which the number of feedbacks
                      supported by the device is to be returned.

       mask           Specifies a mask specific to each type of feedback  that
                      describes how the feedback is to be modified.

       control        Specifies  the  address of an XFeedbackControl structure
                      that contains the new values for the feedback.


DESCRIPTION

       These requests are provided to manipulate those input devices that sup-
       port  feedbacks.   A  BadMatch error will be generated if the requested
       device does not support feedbacks.  Whether or not a given device  sup-
       ports feedbacks can be determined by examining the information returned
       by the XOpenDevice request.  For those devices that support  feedbacks,
       XOpenDevice   will   return   an  XInputClassInfo  structure  with  the
       input_class field equal to the constant FeedbackClass (defined  in  the
       file XI.h).

       The  XGetFeedbackControl  request returns a pointer to a list of XFeed-
       backState structures.  Each item in this  list  describes  one  of  the
       feedbacks  supported  by the device.  The items are variable length, so
       each contains its length to allow traversal to the  next  item  in  the
       list.

       The feedback classes that are currently defined are:  KbdFeedbackClass,
       PtrFeedbackClass, StringFeedbackClass,  IntegerFeedbackClass,  LedFeed-
       backClass,  and  BellFeedbackClass.  These constants are defined in the
       file XI.h.  An input device may support zero or more classes  of  feed-
       back, and may support multiple feedbacks of the same class.  Each feed-
       back contains a class identifier and an id that is unique  within  that
       class  for  that input device.  The id is used to identify the feedback
       when making an XChangeFeedbackControl request.

       XGetFeedbackControl can generate a BadDevice or BadMatch error.

       The XChangeFeedbackControl request modifies the values of one  feedback
       on the specified device.  The feedback is identified by the id field of
       the XFeedbackControl structure that is passed with  the  request.   The
       fields  of  the  feedback that are to be modified are identified by the
       bits of the mask that is passed with the request.

       XChangeFeedbackControl can generate a BadDevice, BadMatch, or  BadValue
       error.


STRUCTURES

       Each  class  of  feedback  is described by a structure specific to that
       class.  These structures are defined in the file XInput.h.   XFeedback-
       State  and  XFeedbackControl  are generic structures that contain three
       fields that are at the beginning of each class of feedback:

       typedef struct {
            XID class;
            int length;
            XID id;
       } XFeedbackState, XFeedbackControl;

       The  XKbdFeedbackState  structure  defines  the  attributes  that   are
       returned for feedbacks equivalent to those on the X keyboard.

       typedef struct {
            XID     class;
            int     length;
            XID     id;
            int     click;
            int     percent;
            int     pitch;
            int     duration;
            int     led_mask;
            int     global_auto_repeat;
            char    auto_repeats[32];
       } XKbdFeedbackState;

       The   XPtrFeedbackState  structure  defines  the  attributes  that  are
       returned for feedbacks equivalent to those on the the X pointer.

       typedef struct {
            XID     class;
            int     length;
            XID     id;
            int     accelNum;
            int     accelDenom;
            int     threshold;
       } XPtrFeedbackState;

       The  XIntegerFeedbackState  structure  defines  attributes   that   are
       returned for integer feedbacks.

       typedef struct {
            XID     class;
            int     length;
            XID     id;
            int     resolution;
            int     minVal;
            int     maxVal;
       } XIntegerFeedbackState;

       The  XStringFeedbackState  structure  defines  the  attributes that are
       returned for string feedbacks.

       typedef struct {
            XID     class;
            int     length;
            XID     id;
            int     max_symbols;
            int     num_syms_supported;
            KeySym  *syms_supported;
       } XStringFeedbackState;

       The  XBellFeedbackState  structure  defines  the  attributes  that  are
       returned for bell feedbacks.

       typedef struct {
            XID     class;
            int     length;
            XID     id;
            int     percent;
            int     pitch;
            int     duration;
       } XBellFeedbackState;

       The   XLedFeedbackState  structure  defines  the  attributes  that  are
       returned for LED feedbacks.

       typedef struct {
            XID     class;
            int     length;
            XID     id;
            int     led_values;
       } XLedFeedbackState;

       The XPrtFeedbackControl structure defines the attributes  that  can  be
       controlled for pointer feedbacks.

       typedef struct {
            XID     class;
            int     length;
            XID     id;
            int     accelNum;
            int     accelDenom;
            int     threshold;
       } XPtrFeedbackControl;

       The  XKbdFeedbackControl  structure  defines the attributes that can be
       controlled for keyboard feedbacks.

       typedef struct {
            XID     class;
            int     length;
            XID     id;
            int     click;
            int     percent;
            int     pitch;
            int     duration;
            int     led_mask;
            int     led_value;
            int     key;
            int     auto_repeat_mode;
       } XKbdFeedbackControl;

       The XStringFeedbackControl structure defines the attributes that can be
       controlled for string feedbacks.

       typedef struct {
            XID     class;
            int     length;
            XID     id;
            int     num_keysyms;
            KeySym  *syms_to_display;
       } XStringFeedbackControl;

       The  XIntegerFeedbackControl  structure defines the attributes that can
       be controlled for integer feedbacks.

       typedef struct {
            XID     class;
            int     length;
            XID     id;
            int     int_to_display;
       } XIntegerFeedbackControl;

       The XBellFeedbackControl structure defines the attributes that  can  be
       controlled for bell feedbacks.

       typedef struct {
            XID     class;
            int     length;
            XID     id;
            int     percent;
            int     pitch;
            int     duration;
       } XBellFeedbackControl;

       The  XLedFeedbackControl  structure  defines the attributes that can be
       controlled for LED feedbacks.

       typedef struct {
            XID     class;
            int     length;
            XID     id;
            int     led_mask;
            int     led_values;
       } XLedFeedbackControl;


DIAGNOSTICS

       BadDevice   An invalid device was specified.  The specified device does
                   not  exist or has not been opened by this client via XOpen-
                   InputDevice.  This error  may  also  occur  if  some  other
                   client has caused the specified device to become the X key-
                   board or X pointer device via the XChangeKeyboardDevice  or
                   XChangePointerDevice requests.

       BadMatch    This  error may occur if an XGetFeedbackControl request was
                   made specifying a device  that  has  no  feedbacks,  or  an
                   XChangeFeedbackControl  request was made with an XFeedback-
                   Control structure that contains an invalid  feedback  type.
                   It may also occur if an invalid combination of mask bits is
                   specified (DvKey but no DvAutoRepeatMode for keyboard feed-
                   backs),  or  if an invalid KeySym is specified for a string
                   feedback.

       BadValue    Some numeric  value  falls  outside  the  range  of  values
                   accepted  by  the XChangeFeedbackControl request.  Unless a
                   specific range is specified for an argument, the full range
                   defined  by  the argument's type is accepted.  Any argument
                   defined as a set of alternatives can generate this error.


SEE ALSO

       Programming With Xlib

X Version 11                      libXi 1.0.2        XGetFeedbackControl(3X11)

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